I have a pure distilling reflux with the 600ml extension, and a needle valve instead of the little restriction valve at the output.
The output is very slow, I have stuffed around with the boiler temperature, I have now 22000 litres of cooling, but as the run gets on in time ( couple of hours) the output at best is a fast drip. I don't mind that with the heads, but would like a steady stream when in the hearts.
My guess is the top of the column and the output copper pipe heats up over time reducing or restricting the evaporation rate
I was wondering whether a leibig condenser added to the needle valve will help the output flow as I feel the standard condenser doesn't seem to be doing the job
Am I on the right track or is there another factor I don't know about